Green Cross Australia is a not for profit organisation who deliver digital projects that help people in practical ways adapt to our changing climate, embrace sustainable living and build resilient communities. Find out about our other projects…

Green Building Guide

Building Materials

The types of materials selected at the design stage of building
a home will impact fundamentally on its longer-term sustainability.
These choices have implications for saving energy, improving
bushfire resilience and improving comfort.

Building materials typically considered to be 'green' include
renewable plant materials like straw and mud brick, timber from
forests certified to be sustainably managed, recycled materials and
other products that are non-toxic, reusable and renewable.

Concrete is an excellent material for
creating thermal mass in a passive solar designed home. In
temperate and cool climates thermal mass helps regulate a home's
temperature and keep it warm in winter and cool in summer.

These are a relatively new building
system that started in Australia with thermacell blocks. Generally,
these systems consist of a range of wall blocks and corner blocks
that are assembled onto a solid foundation, such as concrete slab
or footings, to make a complete wall.

Timber is probably the most commonly used building material
there is. It is strong, flexible, readily available and providing
it is sourced properly, is a renewable resource. It is an easy
material to work with and requires relatively basic skills, making
it ideal for owner-builders.

Mudbricks are pretty much what they sound like - bricks made of
mud. Often, they are made on site from local soil, providing there
is enough clay content. The soil is mixed with water and
reinforcing materials such as straw and even cement and then
pressed into wooden forms and allowed to set. The forms are removed
and the bricks set aside to dry for up to several weeks. As they
are made from natural materials they are a sustainable, recyclable,
non-toxic and healthy form of building construction.

Strawbale building like mudbrick is a good sustainable choice as
it is made from natural materials they are a sustainable,
recyclable, non-toxic and healthy form of building construction.
Rectangular strawbales are stacked up to form walls, fixed in place
with metal or wooden pins, and then trimmed and shaped (often using
a chainsaw!) before being rendered with mud or cement based
renders.

Timbercrete is an interesting material, being a combination of
timber waste (sawdust) from various sources and concrete. This
results in a material that is lighter than solid concrete, but of
greater strength and with better insulating capabilities. Some
Timbercrete products can produce walls with R ratings of 3.7, which
is higher than most other materials except strawbale.

Rapidwall is a load-bearing wall construction system that uses
large prefabricated panels to assemble both inner and outer walls
in one go. The panels are made of fibreglass reinforced water
resistant gypsum plaster which is moulded to the required size.
Panels are available up to 12 metres long and 3 metres high, so
entire walls can be prefabricated and then installed onsite using a
crane.

Common clay house bricks as a building material have the
advantage of high thermal mass, so they can be used to store or
absorb heat to help provide temperature stability inside a home.
However, to do this, they must be on the inside of a home, not on
the outside.

Not to be confused with mud brick, rammed earth is a precisely
controlled mixture of gravel, clay, sand, cement, and sometimes
lime or waterproofing additives. The contents are carefully
proportioned and mixed, and then machine-compacted in removable
formwork to yield a stone-like wall that is massive, water
resistant, load bearing and long lasting.